1. Field of the Invention
The present invention relates in general to marker posts and more particularly concerns a marker post which will flex on impact and return to its previous upright position.
2. Description of Related Art
Marker posts have many uses, among them are marking paths, driveways, roads and holding up road signs. There are basically two types of marker posts, solid and semi-flexible. The solid marker post, upon impact, will either break in two, move completely or remain as it was before the impact. In all these situations extreme damage can occur to the marker post, the ground around the marker post and in particular, the impacting object.
The semi-flexible marker post is available in two versions, one will bend and not return to its previous position and the other will bend and return to its upright position.
The first version will bend and have to be manually straightened for the marker post to serve any purpose. This type is usually made from a soft aluminum. The second type of semiflexible marker post will flex and return to its upright position as long as it is impacted in the direction it is designed to flex. This version is described and covered in U.S. Pat. No. 4,862,823 entitled "Bendable Marker and Method of Marking". If the marker is hit in the direction that it is not designed to flex it is like a solid marker post. Another limitation with this type of marker post is that its flexing ability is gained through a flexible elastomic element or more simply a piece of plastic. The flexible plastic in this type of marker post may lose its strength or crack over time thereby not allowing it to return completely upright after impact.
A totally different type of marker post is the type covered by U.S. Pat. No. 3,371,647 entitled "Athletic Field Marker". The marker post covered by this patent is made of foam. This marker post is useful from the point of view of not causing damage to the impacting object but it lacks rigidity. The foam is soft and weak and can only be a certain length without requiring structural modifications to hold the marker up.
Another difficulty with most currently available markers are that they are of one piece construction which makes them difficult to install if they are of substantial height.